It is known to manufacture nitrogen-containing organic compounds, such as ureas and carbamates, by methods of synthesis which require the catalytic insertion of carbon monoxide into the &gt;NH-- bonds of compounds containing at least one amino group, in the presence of metal catalysts, and in a liquid reaction medium containing a nitrogen-containing organic base.
Thus, Patent GB-A No. 1,275,702 (ASAHI KASEI and CHIYODA KAKO) discloses a process for the manufacture of ureas or of urea derivatives by reaction of ammonia or of an amine with carbon monoxide in the presence of selenium. The reaction is preferably carried out in the presence of oxygen and of a basic solvent such as triethylamine or a tertiary amine. Other basic solvents, such as tetrahydrofuran and pyridine, have also been used to carry out this reaction (Journal of American Chemical Society, 1971, volume 93, No. 23, page 6344).
K. Kondo and colleagues have described the synthesis of carbamides by reaction of esters of aminoacids with carbon monoxide and oxygen in the presence of a catalyst comprising selenium and triethylamine (Synthesis, 1979, No. 9, pages 735-736).
The manufacture of carbamates from amines, alcohols, carbon monoxide and oxygen has been described by K. Kondo and colleagues in Chemistry Letters, 1972, No. 5, pages 373-374. This document discloses the use, in this reaction, of primary aromatic amines, selenium and triethylamine.
These methods of synthesis of the abovementioned nitrogen-containing organic compounds, however, suffer from certain disadvantages. The productivity of the reactors is low because the reactions are excessively slow, in spite of the use of high pressures and high temperatures, or the yield of the reactions is mediocre, or the selectivity in respect of the desired final product is poor and a large quantity of undesirable byproducts is obtained.